Rocker arm assembly and method of lubricating a valve train

ABSTRACT

A method of lubricating one or more valve train ( 100 ) components includes delivering a lubricating fluid to the inner cavity ( 156 ) of a fluid collecting member ( 152 ) through a radially extending discharge portion ( 182 ) of a fluid passage ( 176 ) in a rocker arm insert. The insert fluid passage ( 176 ) is in fluid communication with a lubricating fluid source to dispense a controlled amount of lubricating fluid to one or more valve train components during operation of an engine. The radially extending discharge portion of the fluid passage in the insert may be positioned adjacent to a spherical end cap that is received in the inner cavity of the fluid collecting member.

TECHNICAL FIELD

The present disclosure relates generally to a method of lubricating avalve train and, more particularly, to a method of lubricating one ormore valve train components including dispensing a lubricating fluidthrough a hole extending radially through a rocker arm insert.

BACKGROUND

Internal combustion engines, including diesel engines, gasoline engines,gaseous fuel-powered engines, and other engines known in the art,typically include a valve train. The valve train includes intake andexhaust valves in a combustion chamber and a mechanism to cause thevalves to open and close. The valve train may include a rocker arm thatis pivoted through engagement with a cam positioned on a rotatingcamshaft to generate the required opening and closing of the intake andexhaust valves. In some instances the valve train may include ahydraulic lash adjuster (HLA) to maintain the desired valve lift andeliminate the need for periodic adjustment of the valves. A lubricatingmechanism may also be provided in the valve train to lubricate valvetrain components during operation.

U.S. Patent Application Publication No. 2003/0037744 to Yates (the '744publication) discloses a method of retaining a rocker lever ball socketon a rocker lever ball of a rocker lever. The rocker lever ball includesa first fluid channel in fluid communication with an engine and therocker lever ball socket includes a second fluid channel. The first andsecond fluid channels align at a predetermined rotation of a rockerlever shaft to complete a fluid path to the exterior of the rocker leverball socket. However, the lubrication method contemplated by the '744publication is not ideal in all valve trains and can result ininsufficient or excessive lubrication under certain conditions.

The method and apparatus of the present disclosure alleviates one ormore deficiencies of the prior art.

SUMMARY OF THE INVENTION

Another aspect of the present disclosure relates to a rocker arm insertassembly comprising: a rocker arm including a first fluid passagetherein; and an insert including a first end carried by the rocker arm,a second end opposite the first end, and a second fluid passage, whereinthe second fluid passage in the insert is in fluid communication withthe first fluid passage in the rocker arm and the second fluid passageincludes a discharge portion extending radially to an outer surface ofthe insert.

One aspect of the present disclosure relates to a method of lubricatingone or more valve train components comprising the steps of supplying alubricating fluid to a fluid passage in an insert in a rocker arm, theinsert having a first end carried by the rocker arm and a second endmovably secured to a fluid collecting member; and dispensing thelubricating fluid onto the fluid connecting member through a radiallyextending discharge portion of the fluid passage in the insert.

One aspect of the present disclosure relates to a rocker arm assemblycomprising a rocker arm including a first fluid passage therein; and aninsert having a first end carried by the rocker arm, a second endopposite the first end and adapted to be movably connected to a fluidcollecting member, and a second fluid passage in the insert, wherein thesecond fluid passage in the insert is in fluid communication with thefirst fluid passage in the rocker arm and the second fluid passageincludes an axial portion extending longitudinally along the insert anda discharge portion extending radially to an outer surface of theinsert, the discharge portion being positioned to deliver lubricatingfluid to the fluid collecting member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective diagrammatic view of part of a valve trainincluding a rocker arm assembly according to the concepts of the presentdisclosure;

FIG. 2 is a section diagrammatic view of the rocker arm assembly asindicated in FIG. 1;

FIG. 3 is a section view of a rocker arm including a rocker arm insertaccording to the concepts of the present disclosure, as indicated inFIG. 1; and

FIG. 4 is a section view of a rocker arm insert and fluid collectingmember according to the concepts of the present disclosure;

DETAILED DESCRIPTION

Referring now to FIG. 1, a portion of a valve train is depicted and isindicated generally by the numeral 100. Valve train 100 is asub-assembly of an internal combustion engine and generates thenecessary opening and closing of the intake and exhaust valves in thecombustions chambers.

Valve train 100 includes one or more rocker arms 102 mounted on andcapable of pivoting about a rocker arm shaft 104 (FIG. 2). Although notshown in FIG. 1, each rocker arm shaft 104 extends along at least aportion of the length of an engine adjacent to the intake and exhaustvalves 106 and 108. The rocker arm shaft 104 may include a passage 107configured to convey lubricating fluid from a lubricating fluidreservoir such as an engine, for example, through the rocker arm shaft104 to one or more valve train components. As best shown in FIG. 1, therocker arms 102 are axially spaced so that they each align with intakeor exhaust valves, 106 and 108 respectively. A camshaft 111 includes aplurality of axially spaced cams 110 to provide the desired timing tothe valve train. A connecting rod 112 extends between each of the cams110 on the camshaft 111 and a hydraulic lash adjuster (HLA) 113 that ispositioned at one end of and engaged with the rocker arm 102. Eachconnecting rod 112 may include a roller assembly 109 that engages thecam 110 on the camshaft 111.

Referring to FIG. 2, the HLA 113 may include a body 114 and a plunger116, each having an internal oil cavity. The oil may flow into a lowpressure chamber 118 in the plunger 116 and then may pass through aone-way valve 120 into a high pressure chamber 122 within the body 114.The plunger 116 may slide within the body 114 to increase the effectivelength of the HLA 113, thereby taking up any clearance within the valvetrain. The one-way valve 120 may prevent the plunger 116 from retractinginto the body and thereby decreasing the effective length of the HLA113.

In operation of the engine the roller assembly 109 rides on the outersurface of the cam 110 to generate a reciprocating motion of theconnecting rod 112, causing pivoting of the rocker arms 102 about therocker arm shaft 104. The number and spacing of the rocker arms 102 andcams 110, and the related components, may vary depending upon theparticular size and design of the engine, and in particular dependingupon the number of intake and exhaust valves 106 and 108.

Referring now to FIGS. 2 and 3, rocker arm 102 will be described ingreater detail. Each rocker arm 102 includes a body 124 having a hole126 adapted to receive a rocker arm bearing 128. Rocker arm bearing 128may be positioned within the hole 126 to rotatably support the rockerarm shaft 104 (FIG. 2) to reduce friction forces and facilitate pivotingof the rocker arm about the shaft, as is customary. The rocker armbearing 128 may include one or more openings or channels 130 (FIG. 3) toallow for fluid transfer from the rocker arm shaft 104. The hole 126through body 124 may be generally cylindrical in shape, and the bearing128 may be generally annular in shape with an outer diameter generallycorresponding to the inner diameter of the 126.

As best seen in FIG. 3, the body 124 of the rocker arm 102 includes afirst arm 132 extending in a first radial direction away from the hole126 and a second arm 134 extending in a second radial direction awayfrom the hole 126. One or both of the first and second arms 132, 134 mayhave a reduced cross sectional area as it extends away from the hole 126in the body 124. The first arm 132 may include a first enlarged endportion 133 at an end opposite the hole 126, the first enlarged endportion 133 adapted to receive an insert therein. Similarly, the secondarm 134 may include a second enlarged end portion 135 at an end oppositethe hole 126, the second enlarged end portion 135 adapted to receive aninsert therein. One or both of the first and second enlarged endportions 133, 135 may have a generally cylindrical outer surface, thecylindrical outer surface defining a center axis that is orientedgenerally perpendicular to the axis of rotation of the rocker arm shaft104.

A first bore 136 may be provided in the first enlarged end portion 133of the first arm 132. The first bore 136 may be generally cylindrical inshape and may be positioned substantially concentrically within thefirst enlarged end portion 133. Thus, the first bore 136 may have acenter axis that is oriented generally perpendicular to the axis ofrotation of the rocker arm shaft 104. In an exemplary embodiment, thefirst bore 136 may be a blind bore extending less than entirely throughthe first enlarged end portion 133 of first arm 132. However, it is alsocontemplated that a through bore may be provided that extends though theentirety of the first enlarged end portion 133.

Similarly, a second bore 138 may be provided in the second enlarged endportion 135 of the second arm 134. The second bore 138 may be generallycylindrical in shape and may be positioned substantially concentricallywithin the second enlarged end portion 135. Thus, the second bore 138may have a center axis that is oriented generally perpendicular to theaxis of rotation of the rocker arm shaft 104. In the embodimentdepicted, the second bore 138 is a through bore that extends through theentirety of the second arm 134. However, similar to first bore 136, thesecond bore 138 may alternatively be provided as a blind bore.

A first rocker arm insert 140 may be carried by and extend from thefirst enlarged end portion 133. At least a portion of the first rockerarm insert 140 may be received in the first bore 136 and secured thereinto resist removal. Similarly, a second rocker arm insert 142 may becarried by and extend from the second enlarged end portion 135. At leasta portion of the second rocker arm insert 142 may be received in thesecond bore 138 and secured therein to resist removal. The first andsecond rocker arm inserts 140, 142 may be secured in the first andsecond bores 136, 138, respectively, by any method or mechanism known tothose skilled in the art, including, but not limited to, a press fit, athreaded attachment, or other mechanical retention system.

The first rocker arm insert 140 may include body member 144 having afirst end 146 and a second end 148 located on opposing longitudinal endsof the body member 144. The axial distance between the first end 146 andsecond end 148 defines a longitudinal length L of the first rocker arminsert 140. At least a portion of the body member 144 adjacent to thefirst end 146 may have a shape, as defined by an outer surface 150, thatis adapted to be received in the first bore 136 in the first arm 132 ofthe rocker arm body 124.

The second end 148 of the first rocker arm insert 140 may be movablyconnected to a fluid collecting member 152 to allow the first rocker arminsert 140 to pivot relative to the fluid collecting member 152. In anexemplary embodiment, the second end 148 of the first rocker arm insert140 may include a spherical cap 154, and the fluid collecting member 152may include an inner cavity 156 having a generally spherical wellportion 157. The spherical cap 154 may be formed by a generallyspherical end portion having a shoulder 158 defined by an intersectingplane on an upper side of the spherical end portion. The spherical cap154 and the generally spherical well portion 157 together form aball-and-socket type joint that allows a degree of rotational movementbetween the fluid collecting member 152 and the first rocker arm insert140. While a particular movable connection has been described herein andshown in the drawings, it is also contemplated that other known movableconnecting mechanisms may be used to movably secure the first rocker arminsert 140 to the fluid collecting member 152.

The fluid collecting member 152 may further include an annulardepression 160 at a top edge of the generally spherical well portion157, the annular depression 160 having an increased diameter D₄ ascompared to the diameter D₃ of the generally spherical well portion 157and providing an increased volume of the inner cavity 156 formed withinthe fluid collecting member 152 (see FIG. 4). In exemplary embodiments,the annular depression 160 may have a diameter D₄of betweenapproximately 8 and 24 mm. The inner cavity 156 in the fluid collectingmember 152 may include an upper opening 162 having a diameter D₅approximately equal to the diameter D₃ of the generally spherical wellportion 157.

The spherical cap 154 of the insert may have a diameter D₁ larger thanthe diameter D₂ of the body member 144 and approximately equal to thediameter D₃ of the generally spherical well portion 157 in the fluidcollecting member 152. Thus, the dimensional relationship of thecomponents may be described as follows:

D ₂<(D ₁ , D ₃ , D ₅)<D ₄

where D₁ is the diameter of the spherical cap 154, D₂ is the diameter ofthe body member 144, D₃ is the diameter of the generally spherical wellportion 157, D₄ is the diameter of the annular depression 160 and D₅ isthe diameter of the upper opening 162.

The diameter D₁ of the spherical cap 154, and therefore the approximatediameters D₃ and D₅ of the generally spherical well portion 157 and theupper opening 162 respectively, may be between approximately 7 and 22mm, in other embodiments between approximately 10 and 20 mm, and in yetother embodiments between approximately 12 and 17. In an exemplaryembodiment, the diameter D₂ of the body member 144 may be betweenapproximately 4 and 10 mm and the diameter D₅ of the upper opening maybe between 7 and 22 mm.

The inner cavity 156 of the fluid collecting member 152 may have aheight H₁ measured from the bottom of the spherical well portion 157 toa top surface 153 of the fluid collecting member 152 adjacent to theupper opening 162 that is between approximately 4 and 12 mm, and in anexemplary embodiment is approximately 10 mm.

In particular embodiments, the fluid collecting member 152 may beprovided in the form of a rocker arm button positioned on a top surfaceof a bridge 163 (FIG. 2) that extends between two adjacent valveretainers projecting from the intake valves 106 or exhaust valves 108.The generally spherical cap 154 of the first rocker arm insert 140 andthe generally spherical well portion 157 in the fluid collecting member152 may allow for pivoting movement between the rocker arm 102 and thebridge 163.

Referring back to the first rocker arm insert 140, as best shown in FIG.3, a rocker arm fluid passage 166 extends through the rocker arm body124 from an opening 168 at the inner surface of the hole 126 andterminates at an opening 170 in the first bore 136. A substantiallycircumferential recess 164 may be provided in the outer surface 150 ofthe body member 144 adjacent to the first end 146. This circumferentialrecess 164 may create a generally circumferential fluid chamber betweenthe first rocker arm insert 140 and the first bore 136. The opening 168in the hole 126 may be aligned with the bearing channel 130 in therocker arm bearing 128, and the opening 170 in the first bore 136 is influid communication with the circumferential recess 164. In a particularembodiment, the rocker arm fluid passage 166 may be formed as a throughbore, thereby creating an access bore 172 extending from the first bore136 to an end of the first arm 132 of the rocker arm body 124. Thisaccess bore 172 may be sealed by a plug or gasket 174, or other sealingmechanisms known to those skilled in the art.

An insert fluid passage 176 can extend through at least a portion of thefirst rocker arm insert 140 and may have an opening in the outer surface177 of the spherical cap 154. The insert fluid passage 176 may includean axial portion 178 extending longitudinally along the first rocker arminsert 140 at least partially between the first end 146 and second end148. In a particular embodiment the axial portion 178 of the insertfluid passage 176 may be a blind bore extending from the outer surface177 of the spherical cap 154 to an end point 179 adjacent to the firstend 146. A radial inlet passage 180 may extend through the first rockerarm insert 140 between the axial portion 178 of the insert fluid passage176 and the circumferential recess 164 to facilitate fluid communicationbetween the rocker arm fluid passage 166 and the insert fluid passage176.

The insert fluid passage 176 may also include a discharge portion 182extending radially from the axial portion 178 to the outer surface 150of the first rocker arm insert 140. The discharge portion 182 may belocated in the body member 144 of the first rocker arm insert 140adjacent to the spherical cap 154. The discharge portion 182 may definean exit orifice 184 in the outer surface 150 of the body member 144. Theexit orifice 184 may be positioned adjacent to the shoulder 158 of thespherical cap 154. In an exemplary embodiment the discharge portion 182may extend at an approximate right angle relative to the axial portion178 of the insert fluid passage. However, it is contemplated that thedischarge portion 182 may be alternatively oriented relative to theaxial portion 178 while extending radially toward the outer surface 150,such as, for example, by extending at an approximately 45 degree anglerelative to the axial portion 178.

In certain embodiments, the discharge portion 182 of the first rockerarm insert 140 may have a diameter of less than approximately 1.75 mm(0.07 inch), in other embodiments a diameter of less than approximately1.70 mm (0.07 inch), and in yet other embodiments a diameter of lessthan approximately 1.65. In the same or other embodiments, the dischargeportion 182 of the first rocker arm insert 140 may have a diameter ofbetween approximately 1.40 and 1.80 mm (0.06 and 0.07 inch), in otherembodiments between 1.45 and 1.75 mm (0.06 and 0.07 inch), and in yetother embodiments between 1.50 and 1.70 mm (0.06 and 0.07 inch). In aparticular embodiment, the discharge portion 182 may have a diameter ofapproximately 1.60 mm (0.06 inch). In an exemplary embodiment the axialportion 178 of the insert fluid passage 176 may have a diameter equal tothe diameter of the discharge portion 182 to allow for manufacturingefficiency.

The exit orifice 184 of the discharge portion 182 may be longitudinallyspaced from a distal end 185 of the spherical cap 154 by a distance H₂of between approximately 4 and 10 mm. The distance H₂ that the exitorifice 184 is spaced from the distal end 185 may be less than theheight H₁ of the inner cavity 156 to ensure that the exit orifice 184 ispositioned within the inner cavity 156 when the first rocker arm insert140 is movably secured to the fluid collecting member 152.

The second rocker arm insert 142 may be similar in many respects to thefirst rocker arm insert 140, and in certain embodiments may besubstantially identical absent the spherical cap 154 feature. However,it is also contemplated that the second rocker arm insert 142 mayinclude distinctions from the first rocker arm insert 140. In anexemplary embodiment the second rocker arm insert 142 may be secured inthe second bore 138 by a nut 186 threaded over a threaded top portion188 of the second rocker arm insert 142.

The second rocker arm insert 142 may be operatively engaged with theconnecting rod 112. In a particular embodiment, the bottom surface 190of the second rocker arm insert 142 may engage the plunger 116 of theHLA 113 (FIG. 2), the HLA being operatively engaged with the connectingrod 112 extending toward the camshaft 111 (FIG. 1). The HLA 113 may bein fluid communication with the rocker arm shaft 104 through one or morefluid passages 192, 194 in the second arm 134 of the rocker arm body 124and second rocker arm insert 142, respectively. Hydraulic fluid may bedelivered through an opening 196 in the bottom surface 190, as definedby the fluid passage 194 in the second rocker arm insert 142, into thelow pressure chamber 118 within the HLA 113.

INDUSTRIAL APPLICABILITY

The disclosed method of lubricating one or more valve train components,and the disclosed rocker arm assembly and rocker arm insert, may beuseful in any internal combustion engine including diesel engines,gasoline engines, gaseous fuel-powered engines, and other engines knownin the art. More particularly, the disclosed method and apparatus may beuseful in an internal combustion engine that includes an HLA within thevalve train. The HLA may render known valve train lubrication methodsand mechanisms ineffective due, at least in part, to reduced clearancesbetween components of the valve train.

The method of the present disclosure contemplates lubricating one ormore components of the valve train by dispensing lubricating fluid froma radial discharge portion 182 of a fluid passage 176 in a rocker arminsert. The lubricating oil is provided to the rocker arm bearing 128 bya hole in the rocker arm shaft 104. The oil then travels through therocker arm fluid passage 166 in the first arm 132 of the rocker arm body124. The lubricating fluid then flows from the rocker arm fluid passageinto the insert fluid passage 176 and exits from the insert through aradial discharge portion 182 and exit orifice 184. The lubricating fluidmay then be captured by the inner cavity 156 in the fluid collectingmember 152, thereby minimizing the amount of oil mist generated, whichin turn may minimize the oil load on a crankcase ventilator mountedadjacent to the rocker arm assembly.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the method of lubricating avalve train and rocker arm insert of the present disclosure withoutdeparting from the scope of the disclosure. Other embodiments will beapparent to those skilled in the art from consideration of thespecification and practice of the method and device disclosed herein. Itis intended that the specification and examples be considered asexemplary only, with a true scope of the disclosure being indicated bythe following claims and their equivalent.

What is claimed is:
 1. A rocker arm assembly comprising: a rocker armincluding a first fluid passage therein; and an insert including a firstend carried by the rocker arm, a second end opposite the first end, anda second fluid passage, wherein the second fluid passage in the insertis in fluid communication with the first fluid passage in the rocker armand the second fluid passage includes a discharge portion extendingradially to an outer surface of the insert.
 2. The rocker arm assemblyof claim 1, the second fluid passage in the insert including an axialportion extending between the first end and the discharge portion. 3.The rocker arm assembly of claim 1, further comprising a radiallyextending inlet passage extending from the outer surface of the insertto the second passage adjacent to the first end of the insert.
 4. Therocker arm assembly of claim 3, further comprising a recess in the outersurface in axial alignment with the radially extending inlet passage. 5.The rocker arm assembly of claim 1, wherein said second fluid passage,including the discharge portion, has a diameter of between approximately1.4 and 1.8 mm.
 6. A method of lubricating one or more valve traincomponents comprising the steps of: (a) supplying a lubricating fluid toa fluid passage in an insert in a rocker arm, the insert having a firstend carried by the rocker arm and a second end movably secured to afluid collecting member; and (b) dispensing the lubricating fluid ontothe fluid connecting member through a radially extending dischargeportion of the fluid passage in the insert.
 7. The method of claim 6,wherein the step of supplying a lubricating fluid includes deliveringthe lubricating fluid to the rocker arm through a rocker arm shaft. 8.The method of claim 7, wherein the step of supplying a lubricating fluidfurther includes conveying the lubricating fluid from the rocker armshaft through a fluid passage in the rocker arm to the rocker arminsert.
 9. The method of claim 6, further comprising the step ofconveying the lubricating fluid through an axial portion of the passagein the rocker arm insert and then into the radially extending dischargeportion of the fluid passage in the insert.
 10. The method of claim 6,wherein the fluid collecting member is a rocker arm button having arecess that receives the second end of the insert, and wherein thelubricating fluid is dispensed into the recess in the rocker arm button.11. A rocker arm assembly comprising: a rocker arm including a firstfluid passage therein; a fluid collecting member including an innercavity; and an insert having a first end carried by the rocker arm, asecond end received in the inner cavity of the fluid collecting memberand movable relative to the fluid collecting member, and a second fluidpassage, wherein the second fluid passage in the insert is in fluidcommunication with the first fluid passage in the rocker arm and thesecond fluid passage includes an axial portion extending longitudinallyalong the insert and a discharge portion extending radially to an outersurface of the insert and terminating in an exit orifice, the dischargeportion positioned to deliver lubricating fluid to the inner cavity ofthe fluid collecting member.
 12. The rocker arm assembly of claim 11,further comprising a radially extending inlet passage extending from theouter surface of the insert to the axial portion of the second passageadjacent to the first end of the insert.
 13. The rocker arm assembly ofclaim 12, further comprising a recess in the outer surface in axialalignment with the radially extending inlet passage.
 14. The rocker arminsert assembly of claim 11, wherein the inner cavity has a height H₁and the exit orifice is spaced from the second end of the insert by adistance H₂, the distance H₂ being less than the height of the innercavity H₁.
 15. The rocker arm assembly of claim 11, wherein the insertis generally cylindrical in shape and the axial portion of the secondfluid passage is positioned substantially concentrically within theinsert.